Streambank Legacy Sediments in Surface Waters: Phosphorus Sources or Sinks?

Inamdar, Shreeram; Sienkiewicz, Nathan; Lutgen, A.; Jiang, G.; Kan, Jinjun

doi:10.3390/soilsystems4020030

Cited by 15 publications

(8 citation statements)

References 65 publications

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“…Perturbations of sediment and nutrients to stream networks significantly impact hydrologic, biological, and chemical functions in downstream aquatic and riparian environments (Graeber et al, 2012;Inamdar et al, 2012;Walter et al, 2007). Thus, quantification of physical and chemical consequences of legacy sediment influx, including volumes of eroded soil/sediment and associated nutrients, will improve our understanding and modeling of nutrient pollution in Piedmont streams and reservoirs (Inamdar et al, 2020(Inamdar et al, , 2021. Moreover, determining sediment and nutrient volumes is an essential constraint in ongoing efforts to reduce the contributions of non-point source nutrient loading to the eutrophication of rivers and estuaries along the Atlantic coast (e.g., Bhattacharya & Osburn, 2020;Fleming et al, 2019;Lebo et al, 2012;Paerl, 2009;Paerl et al, 2010).…”

Section: Anthropogenic Impacts On Hillslope Erosionmentioning

confidence: 99%

Channel head response to anthropogenic landscape modification: A case study from the North Carolina Piedmont, USA, with implications for water quality

Atkins

Wegmann

Bohnenstiehl

2022

Earth Surf Processes Landf

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European-American settlement of the south-eastern United States introduced agricultural practices that included extensive clearing of forested hillslopes to support food and cash-crop agriculture. This land disturbance has long-term effects on stream morphology by displacing channel heads down-valley, impacting downstream sediment and nutrient supply as channel heads migrate back up-valley towards their pre-disturbance locations. This study investigates 40 stream channels in William B. Umstead State Park in the Piedmont of North Carolina using relationships between local slope and contributing drainage areas to predict channel head locations and compare these to their observed positions. Further, expected eroded sediment and nutrient contributions are quantified using migration distances and sampled soils near channel heads. Of the 40 investigated channel heads, 23 are located down-valley from their predicted location by an average of 174.4 m AE 109.6(1 À σ). Using this distance and average channel cross-sectional area, 1.6 AE 1.4 m 2(1 À σ), the expected future erosion per channel is 282.6 AE 177.6 m 3 (1 À σ).Drainage density was used to extrapolate volumes to the 23 km 2 park using a conservative estimate that 50% of the first-order channel heads will migrate up-valley, implying an additional 90.4 AE 56.8 Â 10 3 m 3 (1 À σ) of sediment is expected to erode from the study area. Finally, scaling these volume estimates to sampled soil nutrient values indicates that approximately 1053 AE 662 t (68% confidence) of carbon, 51 AE 32 t of total nitrogen, and 15 AE 9 t of phosphorus are anticipated to enter the fluvial system in response to channel head migration from within the confines of this state park, representing only 1% of the land area in Wake County. These findings suggest that regional water quality challenges posed by suspended sediments and nutrients will persist for hundreds to perhaps thousands of years from non-point sources as first-order channels continue to erode headward towards their equilibrium landscape positions.

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Section: Anthropogenic Impacts On Hillslope Erosionmentioning

confidence: 99%

Channel head response to anthropogenic landscape modification: A case study from the North Carolina Piedmont, USA, with implications for water quality

Atkins

Wegmann

Bohnenstiehl

2022

Earth Surf Processes Landf

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“…Microbial activities and their underlying ecosystem functions such as denitrification also occur in streambank sediments (Koval, 2011;Sienkiewicz et al, 2020;Weitzman et al, 2014). In general, microbial distribution and functional gene profiles vary with sites and depth, and the balance of nutrient processes (e.g., related to nitrogen [N] or phosphorus [P]) determines whether the riparian zone acts as a sink or as a source of nutrients (Inamdar et al, 2020;Weitzman & Kaye, 2017). Microbial distribution and N cycling genes are also influenced by land use and environmental conditions (Sienkiewicz et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Porewater microbiomes in buried wetland soils: Synergic effects of water chemistry and redox gradients associated with hydrological processes

Kan,

Lazareva,

Oviedo‐Vargas

et al. 2024

Freshwater Biology

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Interstitial water or pore water occupies the space between soil particles and provides “hotspots” and “fluvial networks” for microbial activities in floodplain soil. However, to date, we know very little about the microorganisms living in pore water and how they respond to environmental changes. This study aimed to understand microbial distribution and assemblage in riparian pore waters, and how they respond to water chemistry and redox gradients associated with hydrological processes. We analysed the annual changes of porewater microbial communities from the east and west banks of the White Clay Creek, a site at the Christina River Basin – Critical Zone Observatory, Pennsylvania, USA. Microbial abundances were quantified by epifluorescence microscopy and detailed community structures were characterised by high‐throughput sequencing. Water chemistry and redox gradients were also monitored and recorded, and their interactions with porewater microbiomes were analysed using correlations and multivariate analyses. Abundance of microbial cells increased during summer and late autumn. Wetland porewater microbiomes mainly contained Acidobacteria, Bacteroidetes, Nitrospirae and Proteobacteria, and microbiome structures were easily distinguishable from those in the underlying hyporheic gravel layer. Seasonal dynamics of bacterial community structure in the east and west wetlands were distinct, responding to floodplain topography and associated hydrological/geochemical processes. Iron (Fe)‐cycling bacteria (mainly Gallionellaceae and Rhodoferax spp.) dominated the porewater microbiome, and their relative abundance was significantly higher in the east than the west wetland. Furthermore, Fe‐oxidising bacteria (Gallionellaceae) were negatively correlated with Fe‐reducing bacteria (Rhodoferax spp.) at the east wetland. Microbial abundances (cell density) in pore waters showed similar seasonal patterns across stream banks, but microbial community structure did not. Microbiome assembly in pore water is correlated with water chemistry and redox gradients primarily associated with local hydrological processes. As a consequence of their significance for carbon (C) mineralisation and Fe reduction at terrestrial–aquatic interfaces, microbiomes in riparian pore waters and associated microbial activity play an essential role in C and mineral dynamics. These findings will inform future studies of the response of freshwater ecosystems to hydrological dynamics influenced by global climate change.

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“…Prevailing theory is that P is retained within the stream during low flows and suddenly remobilized during high flows, especially for point-source-affected reaches (Demars et al, 2005;Jarvie et al, 2011Jarvie et al, , 2012Sharpley et al, 2013). Field studies have observed that (a) large amounts of legacy P can accumulate within streambeds (Lannergård et al, 2020;McCallister & Logan, 1978;McDaniel et al, 2009), (b) P retention and remobilization can be highly spatially variable (Casillas-Ituarte et al, 2020;Inamdar et al, 2020), and (c) P retention and remobilization can be highly temporally variable (Jarvie et al, 2005(Jarvie et al, , 2006. To capture these dynamics, a watershed model must explicitly track in-stream P stores and simulate the processes by which P is retained and remobilized.…”

Section: Introductionmentioning

confidence: 99%

Updating SWAT+ to Clarify Understanding of In‐Stream Phosphorus Retention and Remobilization: SWAT+P.R&R

Wallington

Cai

2023

Water Resources Research

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Efforts to reduce riverine phosphorus (P) loads have not been as fruitful as expected or hoped. One reason for the failure of these efforts appears to be that models used for watershed P management have understated and misrepresented the role of in‐stream processes in shaping watershed P export. Here, we update the latest release of the Soil and Water Assessment Tool (SWAT+), a widely used watershed management model, to better represent in‐stream P retention and remobilization (SWAT+P.R&R). We add new streambed pools where P is stored and tracked, and we incorporate three new processes driving in‐stream P dynamics: (a) deposition and resuspension of sediment‐associated P, (b) diffusion of dissolved P between the water column and streambed, and (c) adsorption and desorption of mineral P. The objective of this modeling work is to provide a diagnostic tool that enables researchers to challenge existing assumptions regarding how watersheds store, transform, and transport P. Here, in a first diagnostic analysis, SWAT+P.R&R helps reconcile in‐stream P retention theory (that P is retained at low flows and remobilized at high flows) and a discordant data set in our validation watershed. SWAT+P.R&R results (a) clarify that the theorized relationship between P retention and flow is only valid (for this point‐source affected testbed, at least) at the temporal scale of a single rising‐or‐falling hydrograph limb and (b) illustrate that hysteresis obscures the relationship at longer temporal scales. Future work using SWAT+P.R&R could further challenge assumptions regarding timescales of in‐stream P legacies and sources of P load variability.

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Streambank Legacy Sediments in Surface Waters: Phosphorus Sources or Sinks?

Cited by 15 publications

References 65 publications

Channel head response to anthropogenic landscape modification: A case study from the North Carolina Piedmont, USA, with implications for water quality

Channel head response to anthropogenic landscape modification: A case study from the North Carolina Piedmont, USA, with implications for water quality

Porewater microbiomes in buried wetland soils: Synergic effects of water chemistry and redox gradients associated with hydrological processes

Updating SWAT+ to Clarify Understanding of In‐Stream Phosphorus Retention and Remobilization: SWAT+P.R&R

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